(function(doc, win) {
				var docEl = doc.documentElement,
					resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
					recalc = function() {
						var clientWidth = docEl.clientWidth;
						if(!clientWidth) return;
						if(clientWidth >= 640) {
							docEl.style.fontSize = '100px';
						} else {
							docEl.style.fontSize = 100 * (clientWidth / 640) + 'px';
						}
					};
				if(!doc.addEventListener) return;
				win.addEventListener(resizeEvt, recalc, false);
				doc.addEventListener('DOMContentLoaded', recalc, false);
			})(document, window);